In the past, numerous image forming methods which involve ejecting an ultraviolet-curable material over the liquid surface of an ultraviolet-curable resin liquid by an inkjet process have been proposed (refer to PTLs 1 to 6).
PTL 1 proposes an invention in which colored droplets are applied onto a radiation-curable liquid layer and then curing is carried out so as to obtain a fixed dotted shape with uniform glossiness and without bleeding.
However, this proposal is not for forming a characteristic (cell) pattern that spreads over an entire liquid surface as in the present invention. Also, this proposal greatly differs from the present invention in that a colorant as a second ejection liquid does not spread over the liquid surface of the liquid layer but enters the liquid layer, as seen in FIGS. 1b and 1c used for the proposal.
The invention of PTL 2 is intended to avoid attachment-related interference and is not for forming a (cell) pattern that spreads over an entire liquid surface as in the present invention.
The invention of PTL 3 is intended to prevent bleeding and includes a semi-curing step.
The invention of PTL 4 includes improving air sending and is not for forming a (cell) pattern as in the present invention.
The invention of PTL 5 uses a primer containing a high-boiling-point organic solvent and is not for forming a characteristic (cell) pattern as in the present invention.
As just described, the above prior-art documents are similar to the present invention in that an ultraviolet-curable liquid is ejected over the liquid surface of an ultraviolet-curable material liquid; however, all the above prior-art documents are intended to prevent bleeding and improve glossiness and are not for forming a characteristic (cell) pattern as in the present invention.
PTL 6 gives a Comparative Example in which a liquid A has a higher surface tension than a liquid B; however, the surface tension of the liquid A is relatively small and does not suffice to form favorable patterns. Moreover, although there is an expression of “spreading of dots”, there is neither a mention nor a suggestion of formation of a (cell) pattern where a colorant spreads over an entire surface including parts between adjacent dots, as the colorant is centered at portions to which droplets of the colorant have been ejected.
PTL 7 discloses application of a pattern, formed by ejecting a liquid B over a liquid A, to production of a device; however, the liquid A has a lower surface tension than the liquid B, and it is not that the liquid B uniformly spreads over the liquid surface of the liquid A.